This invention relates to a medical image recording apparatus, a medical image correcting method and recording media.
Generally, when a diagnosis of a medical image obtained from an image creating apparatus such as CR(Computed Radiography) apparatus, FPD(Flat Panel Detector), CT(Computed Tomography) and MRI(Magnetic Resonance Imaging) is carried out, a method of observing hardcopies of record of medical information recorded on transmission record media or reflection record media is often used. As an image recording apparatus recording medical images by forming them on recording media, the method of recording by laser exposure on transmission recording media employing silver salt recording material to form an image is often used. As an image recording apparatus, there is known a dry process type image recording apparatus, which conducts photosensitive heat developing image recording by using a photosensitive heat-developable recording material and a photo-thermosensitive recording material as well as an image recording apparatus using a silver salt recording material which needs a conventional wet type process. These recording materials (heat developable photosensitive ones) will be called films hereafter.
Regarding the abovementioned image recording apparatus, in order to output an image having a good gradation, wedge patterns (test pattern) of plural densities are exposed on the film when films are loaded or at constant intervals, and based on the result of the measurement of the density of the obtained pattern image by a densitometer, a calibration is carried out to correct the relationship between an input image data and the exposure amount of laser. For example, there is considered a structure which automatically corrects dispersion of photosensitive characteristics of heat developable photosensitive film and change of development characteristics of an apparatus (for example, see Patent Document 1).
The density of developed film is affected by the quantity of added heat by a heat roller to the exposed film and by timing of cooling. Especially it is known that the density is unstable on the leading edge and the trailing edge of a film because of the structure of film transportation of the heating means. Therefore, there is considered the structure, wherein a film on which a patch of single density is recorded in the center is used, and the rotating speed of heat roller is adjusted based on the result of the density measurement of the patch carried out to every film so as to correct dispersion of the sensitivity characteristics of the film (for example, see Patent Document 2).
[Patent Document 1] TOKKAIHEI6-233134
[Patent Document 2] TOKAI2003-136782
However, the conventional calibration can not carry out simultaneously the correction of tone characteristics by wedge patterns having plural density levels and the density correction of the leading edge and/or the trailing edge of a film.